Sampling is weird. We're so used to it, it's been such a commonplace part of pop music for so long (since the late 1980s), that it's easy to lose sight of what a peculiar thing it is. Although sampling is often compared with collage, I think there's a profound difference which relates to the added dimension of time that music inhabits. With recorded music, however much it's doctored and enhanced through studio techniques (multitracking, overdubs etc), there generally remains a kernel of life inside it; what you are hearing is a sequence of human actions happening in real-time. (I'm talking about played music here, as opposed to programmed music. But it is overwhelmingly the case that played music is what gets sampled – music of the 70s particularly, when analogue recording quality was at its peak but drum machines and sequencers had yet to replace tight rhythm sections.) To take a chunk of living time – which is what a sample is – and chain it into a loop isn't just appropriation, it's a form of enslavement. But to pluck several different segments of live playing from separate space-time contexts and force them into unholy congress with each other … that's sorcery.

When sampling first made waves in the mid-80s, most journalistic discussions focused on the legal aspect, typically framing the samplers in punk-like terms as renegade, naughty, larcenous, irreverent. Likewise, academic studies of sampling in pop over the ensuing decades have largely concerned themselves with copyright and corporate power, typically siding with "the streets" versus the entertainment-media complex. These are perennially interesting issues, for sure, especially when given a postcolonial inflection: not just pirating and bootlegging, but the fact that non-western or pre-capitalist folk cultures typically have much looser, more collective notions of authorship and originality. (A friend of mine who's both a DJ and a law student is currently doing dissertation research in Jamaica looking at the "fluid" – a euphemism – notion of copyright in dancehall culture.) None the less, there appears to other crucial dimensions to sampling – its aesthetics and its philosophical implications – that are relatively neglected. (I could be wrong here, of course, and if you know of really penetrating and provocative work in this area, please point me in its direction!)

What got me thinking about all this was the arrival several weeks ago of an advance CD called Protected: Massive Samples. It's the second in a series started by Rapster Records compiling the original tracks that a well-known group has sampled, in this case Massive Attack. The first volume, released a year ago, was Discovered: A Collection of Daft Funk Samples, which showcased raw material for all those hot hits by Daft Punk. These compilations have not been done as a collaboration with, or even with the blessing of, the group in question; the titles and packaging take great care not to use either band's full name at any point, presumably for legal reasons. And I wonder if Daft Punk or Massive Attack are happy about having their sources so clearly signposted.

The sample-source album isn't a brand new idea. When Kanye West was first blowing up circa The College Drop-out, I recall a vinyl bootleg LP in circulation that collated the tunes he'd sampled, such as Chaka Khan's Through the Fire – the basis for his Through the Wire (although "virtual entirety of" would be nearer the mark, give or take the drums and West's rhymes). I expect there have been other such unofficial compilations. I didn't buy the Kanye Samples record because I was reluctant to interfere with my enjoyment of his album. Similarly I was slightly nervous about playing Protected: Massive Samples the first time. Would I ever be able to listen to Blue Lines the same way again? Would knowing the extent of Massive's debts diminish my admiration, sabotage my sense of awe at their achievement?

This dilemma is unique to pop music of the post-sampling era. There's no counterpart in other artforms that I can think of. It's not like looking at the sketches for a painting, or the rushes for a movie, or even like seeing the original movie from which remake is based. It's sort of like a scenario where you venerate a particular painting and then get presented with tubes of the specific colors of oil paint the artist used on that work. Except not really, because the groove of Billy Cobham's Stratus simply is – in a direct and exact and supremely concrete way – the groove of Massive's Safe from Harm. So we're back to that idea of the sample as a living thing, a portion of time and energy wrested away from its original owners and put to service. Idea for a feature: track down the players on that Cobham session and find out what they really think and feel about being used in this manner. I assume Cobham, as composer of the tune, has at least been remunerated (he gets a credit on Safe from Harm) but quite possibly not the other players (Jan Hammer, Lee Sklar, Tommy Bolin). It's not just about the money, though, it's about having one's performance taken out of its context, severed from its original artistic intent. For what is interesting about comparing Stratus with Safe from Harm is how much all the stuff that clearly mattered to Cobham and crew (the noodly, improvised jazziness – there's a long abstract intro, for instance) gets jettisoned as Massive Attack, being typical B-boys, focus on the driving bass-and-drums groove. Indeed, they focus on the most linear, straightforward segment of the rhythm track, which gets looser and wilder at other points in the song.

I'd heard Stratus before and immediately spotted the Massive connection, so its appearance on Protected didn't surprise me. But I was slightly startled by how extensively Daydreaming – another killer tune from Blue Lines – is based on Mambo by Wally Badarou, a session keyboardist associated with Island Records's Compass Point studios in Nassau, who came to moderate renown in the 80s through his work with Talking Heads, Tom Tom Club, Grace Jones, Black Uhuru and others. Indeed, it makes me want to hunt down Badarou's solo albums to see what other gems are secreted there.

The overall effect of Protected: Massive Samples is less "gotcha" sample-spotting, though, and more like listening to one of those Back to Mine albums: it's a delectably consistent and mood-unified collection of plushly produced, mostly downtempo soul and reggae. Lowrell's Mellow Mellow – the gorgeous source for Blue Lines's Lately – defines the vibe precisely. Getting stoned to these tunes – as you can be sure the Massive boys did on many a Bristol afternoon in the 80s – must have been like lolling around on a gigantic sofa made of marshmallow. Protected also resembles the Under the Influence series: like a photographic negative of a Best Of compilation, it showcases the group's aesthetic through the listening that informed it.

Some self-consciously arty or iconoclastic exponents of sampling recall the appropriation artists of late 70s New York, figures like Sherrie Levine, Richard Prince and Cindy Sherman, whose work involved gambits like copying famous pictures and appending your own signature, or rephotographing photographs (sometimes famous shots, sometimes iconic adverts) and then cropping or otherwise reframing them. That seems quite close to what the early Justified Ancients of Mu Mu did, or avant-pranksters like Plunderphonics and Negativland, where the whole point is sampling a group or song that is universally known and freighted with associations.

But the approach of Massive Attack, Daft Punk and their peers was not based on exploiting familiarity; only the real cratedigging headz ever knew the sources they were drawing on. If the Rapster series continues there's no shortage of potential candidates for this treatment: DJ Shadow, RZA, Chemical Brothers, J Dilla. Most likely the crate-diggers types have got there first and already pulled together unofficial sample-spotting compilations for these artists, and many others besides, for circulation on the web. Similarly, there's a whole site dedicated to identifying samples used in jungle, but for the moment it contents itself with simply citing the source, as opposed to offering MP3s or embedded YouTube audio streams.

Talking of jungle, I'm reminded of how sampling has created a unique and unprecedented form of pop rapture: the epiphany of suddenly, accidentally encountering the source track for a favourite tune. This happens all the time if you are a fan of jungle and hardcore rave. I vividly remember the thrill that ambushed me during a James Bond movie when suddenly I heard a portentous orchestral theme that I'd loved for years as a key element of Acen's 1992 rave classic Trip to the Moon. (The source in question: John Barry's Space March, from his score for You Only Live Twice, soundtracking the moment when a Soviet capsule in orbit is swallowed up by a mysterious shark-like spacecraft).

But probably my all-time favourite sample epiphany relates to a mystery tune, also from 1992, by an artist who trafficked under the period-evocative moniker E. I taped this track off a pirate radio show and have no idea if it ever saw proper release or what its title is. But it's a real lost classic, propelled by the most boombastic breakbeat loop and featuring a comic little vocal hook that coarsely roars "Oi!!!! I've got a little black disc wiv me tune on it!". But there's also an incongruously plangent guitar part and a slow fade where the groove drops away leaving just an aching guitar solo and a totally blissed raver gasping "I... I... I … luvvit!!!". Several years ago, idly channel surfing, I landed midway through The Wall and realised with a shock of delight that the lead guitar on E's tune was actually David Gilmour. But it was only a few months back, once again chancing upon Alan Parker's overripe farrago, that I realised the whole "little black disc" bit was a parody of Nobody Home, specifically the bit that goes "Oi! I've got a little black book with me poems in!"

The French philosopher Paul Virilio argued that every new technology comes complete with its own unique catastrophe; the invention of the aeroplane, for instance, was also the invention of the plane crash. The corollary of the sample epiphany is what I call the "sample stain". But that's a subject I'll return to in a future blogpost.

That first moment that sought to document an act, an idea, a presence, an existence, a deity...that initial spark of creativity born of desire to intensify experience, enhance a space, beautify a body,paint a cave wall, decorate a tool...that first shuffling of utterances, that first gesture, that first rhythm, that first song...that was when we truly became human.--Kevin